Method for flexible pipe welding

ABSTRACT

Method and apparatus are disclosed for welding a pipe extension to a flexible, elongated pipe or hose wherein one end of the pipe is held upright for welding and the other end of the pipe is supported at an angle, such as on a horizontal surface of a cooperating support. The complete pipe including both ends and the intermediate angular section are rotated at substantially constant speed while a bead of weld material is applied in the weld area to give a uniform, leakproof weld. Since the one end of the pipe is upright, the extension may be rested on the end face without clamping and the welding rod is held stationary during welding. The clamp means for holding the welded end of the pipe is carried by a concentric support tube and rotatable cap assembly through which the pipe passes; the cap being stabilized by top and bottom bearings. The clamp includes opposed pivotal jaws on the annular top wall of the rotating cap; the jaws being tightened by screw means at the opposite end. Two-piece split collars are selected to roughly correspond to the outer dimension of the pipe. A fixed chain on the cap is used to drive the same from a motor driven sprocket, which combination retains the cap captive in the axial direction. A pedestal mount adaptor may be used for large diameter pipe.

United States Fatent [19] Flood et al.

[ METHOD FOR FLEXIBLE PIPE WELDING [75] Inventors: Edgar M. Flood,Paducah; William H. Green, Hickory, both of Ky.

[73] Assignee: Weld-Eze, Inc., Paducah, Ky.

[22] Filed: Nov. 17, 1970 [21] Appl. No.: 90,403

[52] US. Cl. ..29/475, 2'9/237, 228/32, 228/45 [51] Int. Cl. ..B23k31/02 [58] Field of Search .....285/l38, 286; 29/475, 477.3, 29/477.7,237; 228/25, 29, 32, 45

- Primary Examiner.l. Spencer Overholser I Assistant ExaminerR. J. CraigAtt0rneyl .owe & King [4 1 Feb. 13, 1973 l 5 7 1 ABSTRACT Method andapparatus are disclosed for welding a pipe extension to a flexible,elongated pipe or hose wherein one end of the pipe is held upright forwelding and the other end of the pipe is supported at an angle, such ason a horizontal surface of a cooperating support. The complete pipeincluding both ends and the intermediate angular section are rotated atsubstantially constant speed while a head of weld material is applied inthe weld area to give a uniform, leakproof weld. Since the one end ofthe pipe is upright, the extension may be rested on the end face withoutclamping and the welding rod is held stationary during welding. Theclamp means for holding the welded end of the pipe is carried by aconcentric support tube and rotatable cap assembly through which thepipe passes; the cap being stabilized by top and bottom bearings. Theclamp includes opposed pivotal jaws on the annular top wall of therotating cap; the jaws being tightened by screw means at the oppositeend. Twopiece split collars are selected to roughly correspond to theouter dimension of the pipe. A fixed chain on the cap is used to drivethe same from -a motor driven 5 Claims, 6 Drawing Figures METHOD FORFLEXIBLE PIPE WELDING The present invention relates to welding, and moreparticularly, to an improved method and apparatus for welding flexiblepipe.

BACKGROUND OF THE INVENTION The use of flexible pipe or hose for fluidtransfer has become very popular in recent years, especially inindustrial processing plants. The flexible pipe is usually fabricated ofstainless steel, bronze, Teflon plastic, or

other strong, corrosion resistant material, and may be fabricated with aplurality of pleats extending around the girth of the pipe. The pipe isflexible by virtue of the pleats expanding on one side and contractingon the other side (in accordion fashion) as the pipe is bent through anangle. The pipe is usuallycovered with a protective metal fabric or wirebraid. The more notable advantages of flexible pipe include (1) theability to extend along a tortuous path without the necessity forforming expensive and leakage-prone joints, and (2) the isolation ofmechanical forces and vibrations between the two connected points.

The flexible pipe must, of course, be provided with a conventionalcoupling at each end in order to be interconnected with the fluidsystem. These couplings, usually in the form of a conventional nipple(male part) or socket (female part) or cooperating flanged collars atboth ends, must be in some manner welded to the body of flexible pipe.This fabrication of flexible pipe ready for installation with couplingsat both ends, is most expediously done on a custom basis by industrialequipment and part distributors at spaced locations around the countrybecause of the virtually infinite number of couplings and the variationin lengths required.

Heretofore, there has not been a simple and efficient machine or methodadaptable for use in custom fabrication of flexible pipe. Insofar as weare aware, fabrication has been performed in all such instances withmakeshift methods, such as tying the flexible pipe to any availablestationary support, tack welding the coupling in position on the endface of the pipe and then applying a head of weld material around theperiphery of the pipe by physical movement of the welding rod around thegirth just as in other conventional methods of welding. Such a methodsuffers from inefficiency in both the time required to complete theprocess and in the quality of the weld obtained. With regard to thelatter, it is extremely difficult to obtain a uniform, high quality weldneeded for the high pressure application to which industrial piping issubjected by free hand movement of the welding rod since a totallysteady hand and uniform forward movement is virtually impossible.

OBJECTIVES OF THE INVENTION Accordingly, it is one object of the presentinvention to provide a simple method and apparatus for welding pipeextensions or couplings to a length of flexible pipe.

It is still another object of the present invention to provide a methodand apparatus-for welding flexible pipe wherein the welded end ispositioned upright and the other end of the pipe is supported at anangle; the pipe including both ends and the intermediate angular sectionbeing rotated at substantially constant speed for applying a uniformbead of weld material.

It is still another object of the present invention to mounted on aconcentric rotating cap, as a fixture for flexible pipe.

BRIEF DESCRIPTION OF THE INVENTION To briefly explain the inventivemethod and apparatus, it can be said that a pipe coupling is welded toan elongated, flexible pipe by rotating the end of the pipe being weldedabout a substantially vertical axis with the pipe coupling or extensionbeing positioned upright on the end face of the pipe. Advantageously,the pipe is supported at the other end at an angle to the vertical axisand preferably along a horizontal surface whereby the height of thewelding fixture does not limit the length of the pipe that may bewelded. Both ends of the pipe and the intermediate angular section arerotated at substantially constant speed to give a uniform weld; it beingunderstood that the intermediate angular section is constantly andsmoothly flexing during rotation to maintain the same angularrelationship at all rotational positions.

Since the end of the pipe being welded is positioned in an uprightmanner by the fixture, the pipe extension or fitting may be convenientlypositioned on top of the pipe in face-to-face contact without additionalclamping means. The formation of the weld bead is automatically governedby the constant rotating action of the pipe and is thus not subject tohuman error so that the weld is always uniform.

In accordance with the invention, the support for the excess length ofpipe is preferably a horizontal surface, such as the floor, so that thepipe rests free under the force of gravity. The fixture is preferablymounted on a stand that is positioned on the floor. In the instancewhere relatively large diameter pipes are welded, a pedestal adaptor ispositioned in the clamp instead of the pipe, with the coupling or pipeextension being mounted on the pedestal and the other end of the pipeextending upwardly or resting in an overhead trough thereby alsoallowing free rotation.

The clamp for the pipe is mounted on a concentric carrier cylinderhaving bearing means at the top and the bottom to cooperate with astationary support thereby assuring lateral stability of the clampedpipe. The clamp itself is preferably formed with at least one pivotaljaw and a tightening bolt to connect the free end of the jaws; atwo-piece split collar being utilized to roughly adapt the clamp tovarious dimension pipe. The drive means includes a chain fixed to theouter periphery of the cylinder, and a sprocket and drive motor assemblyto engage the same; the teeth of the sprocket serving to hold thecylinder captive in the axial direction by engagement with the laterallinks of the chain.

Still other objects and advantages of the present invention will becomereadily apparent to those skilled in this art from the followingdetailed description, wherein there have been shown and described onlythe preferred embodiments of the invention, simply by way ofillustration of the best modes contemplated for carrying out theinvention. As will be realized, the invention is capable of other anddifferent embodiments, and its several details are capable ofmodification in various obvious respects, all without departing from theinvention. Accordingly, the drawings and description are to be regardedas illustrative in nature, and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the weldingfixture of the present invention mounted on a stand and operating on aflexible pipe;

FIG; 2 is a cross-sectional view along line 22 of FIG. 1 looking fromabove the fixture;

FIG. 3 is an enlarged perspective view of the twopiece adaptor collarfor the clamp of the fixture;

FIG. 4 is a perspective view with parts cut away for clarity showing thewelding operation in accordance with the features of the method of thepresent invention;

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 1 showingthe support tube and rotating cap of the fixture; and

FIG. 6 is a side view showing another embodiment of the fixture with apedestal adaptor for welding relatively large diameter pipe.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Making reference toFIG. 1 of the drawings, a welding fixture 10 is shown mounted on a stand11 that is positioned on a floor F. The fixture 10 is suitably held inan upright position by attachment at weld area 12 to platform 13 andsuitable braces 14 extending to legs 15. The welding operator stands orsits on the platform to operate the fixture, as will be more fullyapparent from the discussion below.

The fixture 10 comprises a stationary support tube and a rotatingcylinder or cap 21 mounted for rotation about the top of said tube 20.The upper or end wall 22 of the cap 21 is annular in shape, i.e., acentral opening 23 is provided in the upper wall 22 (see FIG. 2). Aclamp C mounted so as to span the opening 23 includes opposed jaws 24,25 that engage the end of pipe P to be welded. The excess or remainderlength of the pipe includes an intermediate angular section P and theopposite end P all of which rotates during welding by the rotating forcetransmitted through the clamp, as will be seen later. One jaw may befixedly secured to wall 22 by suitable fasteners 26, 27 adjacent theends. The other jaw 25 is pivotally supported at one end by a fastener28 thus making said jaw free to pivot away from the opposed jaw 24 toopen the clamp. A tightening bolt 29 is mounted on the stationary jaw 24about a pivot joint 30 and extends through a slot in the free end of thejaw 25 (see FIG. 4). A nut 31 is applied to bring the jaws toward eachother to effect tightening about the pipe P.

So that various sized pipe may be held in the clamp C, two-piece adaptorcollars, such as the collar shown in FIG. 3 and generally designated bythe reference numeral 35, may be employed. The body portions 36 of thecollar have an outside diameter to fit the semicircular central portionsof the jaws 24, 25, whereas the inside diameter is selected toapproximately fit the particular size of pipe to be welded. Theoverhanging flanges 37 retain the collar in engagement with the jaws 24,25, as shown in FIG. 4.

As best shown in FIG. 5, the support tube 20 has a ring-shaped race 40mounted along the upper end face thereof. Cooperating with the race 40is a plurality of ball bearings 41, which in turn cooperate in a likemanner with the underside of the annular top wall 22, thus forming theother race of a bearing assembly. It will be noted that the cylinder 21is thus held in position in the axial direction or along the verticalaxis by the weight thereof. At the lower peripheral edge of the cap 21are mounted a plurality of radially acting bearing units -that serve tostabilize the cap 21 in. the radial or lateral direction. The rigidstructure of the cap 21 and these bearings around the rigid support tube20 give an extremely stable turmtable on which the pipe P may be clampedand welded.

Around the peripheral lower end of the cap 21 is also fixedly mounted adrive chain to present a suitable means on the cap 21 to apply drivingforce from sprocket S1 and drive motor 52 (see FIG. 2). The drive chainor equivalent structure with lateral connecting links is preferred toother types of drive components, such as gears, since the sprocket teethof the sprocket 51 are operative to engage the sides of the links of thechain 50 and thereby hold the cap 21 in a captive position in the axialdirection on the support tube 20.

Now to consider set-up for welding, the flexible pipe P, havingaccordion-like pleats along its length and a protective sheath of wovenmetal fabric with upper retaining collar 61 therefor, may be insertedthrough the clamp C in an upright position and along a substantiallyvertical axis. In other words, the pipe P to be welded is first threadedfrom the lower portion of the support tube 20 and extended through theopening 23 in the cap 21 and secured in the clamp C. To facilitate thisset-up process, the front of the tube 20 along the lower portion thereofhas an arch-shaped cutout 65 (FIGS. 1 and 5) to allow the operator toeasily extend and control the flexible pipe P for insertion between thejaws 24,25 of the clamp C. Also, the cutout 65 allows the pipe P toassume a more gradual change in direction, i.e., the intermediateangular section I, is allowed to be curved over a larger radius (seedotted line outline in FIG. 1) so that relatively stiff pipe may beaccommodated with ease.

An extension E in the form of a threaded nipple (see FIG. 4) is to bewelded on the end of the pipe in the embodiment illustrated in thedrawings, although it is to be understood that other types of couplingsor even other lengths of pipes may be similarly welded in accordancewith the inventive teachings. This pipe extension E is freely positionedin face-to-face contact on the flat upper end face of the pipe P withoutbeing secured by an outside clamp and without first tack welding, whichwas not possible with the prior art methods described.

In accordance with the present invention, the excess length of the pipeP is left extending from the bottom of the fixture 10 at an angle and isthus no longer a hindrance to successful welding. This is so since theend of the pipe being welded, the intermediate angular section P, andthe opposite end of the pipe I, resting in horizontal position on thefloor F are all rotated in unison, as denoted by the rotational arrowsinFIG. 1. That is, pipe having a length greater than the distancebetween the horizontal surface, such as the floor F, and the end to bewelded, offers no hindrance to the automatic rotation of the pipe sincethe section P, and end P are responsive to rotation. This discoveryallows the use of the simple method of mechanically rotating the pipe ata constant speed and results in gaining a uniform weldment. As will berealized, the length of pipe that may be successfully welded is limitedonly by the space of the room in which the fixture is located and is notdependent upon theaxial dimensions of the fixture itself or the heightof the fixture above the floor F. If necessary or desirable, severalangles or angular sections may be formed in the pipe without effect on ithe efficiency of the welding.

The stand 11 is designed for the welding operator to mount the platform13 during the welding operation. The operator may be suitably situatedon a stool supported by the platform so that he is relaxed'and so thathe has the weld area of the pipe P in the most favorable work positiondirectly in front of him at the most favorable working level.Furthermore, an annular table 66 of wood or other nonconducting materialis pro-' vided upon which the operator can rest his arms for steadyingwhile welding. As shown in FIG. 1, the table 66 is suitably supportedfrom the tube by upstanding arms 67 and an arcuate shield 68 may bepositioned around the edge of the table (also insulated by coupling onlyto table 66) to offer shielding of the bright flash of the weldingoperation from the eyes of fellow employees approaching the fixture fromthe front or sides. Thev operator, comfortably seated on the platform13, may operate at will the welding equipment with a conventionalfoot-operated switch (not illustrated) and the motor 52 with anotherconventional switch (also not shown in the drawings).

The type of actual welding operation to be employed with the fixture 10of the present invention is of course determined by the nature of themetal or plastic material of the pipe P and the coupling E. The mostcommon welding technique is electrical arc welding, and in this case,the ground to the pipe P is obtained through the fixture 10 and thestand 11. Thus, the weld rod or heat generator R is brought intoproximity to weld area A and a uniform bead of weld material B from therod R is deposited as the pipe P and the extension E rotate at aconstant speed. The rod R may be advantageously held stationary and therotation solely relied upon to give the uniform bead of material B.

When welding plastics it is to be understood that the weld rod R mayrepresent an ultrasonic generator to form the weld bead by causing theabutting material of the two parts to flow together, or the rod R mayalternatively be a dispenser of plastic weld material. Also, a separateweld rod or flux apart from rod or heat generator R may be easily usedwith the present inventive method when welding either metal or plasticsinc the other hand of the operator is free.

In some instances, it is desirable to weld relatively large diameterpipe, as represented by the pipe PP illustrated in FIG. 6. Since thepipe is thus too large to be held in the clamp C, a special adaptor inthe form of a pedestal including an upstanding support rod andsupporting base 71 is utilized in accordance with another feature of thepresent invention. The support rod 70 is sized to conveniently fitwithin the clamp C, and thus upon rotation of the cap 21, the base 71will be rotated in a suitable fashion. In the specific arrangementshown, the length of pipe PP has had flanged coupling 72 welded theretoalong with weld bead B,, as illustrated. In order to assure againstpossible accidental displacement of the coupling 72 on the base 71,suitable securing bolt and nuts 74 may be provided. After the flange 72has been welded, the pipe PP is turned upside down and the collar 75 atthe opposite end may be welded in a like fashion.

In a instance where the large diameter pipe PP has an extended length,and it is thus necessary to form an intermediate angular section PP, andallow excess pipe to rest in a horizontal position, as at PP; (notedotted line outline of FIG. 6), itis advantageous to provide an overheadhorizontally extending trough 76. The trough may have suitable rollers77 along the forward edge thereof to permit easier turning of the pipe.Also, the sides of the semicylindrical trough are spaced by a diametersufficient to accommodate the largest pipe, but nevertheless afford aconfining function to protect against the pipe falling.

It will be understood that the large flexible pipe PP will be inherentlystiffer and thus have certain increased resistance to bending andforming the angular section PP,. This means that the coupling 72 mustfirst be tack welded at spaced points around the pipe to resist theupward spring force of the pipe when installed on the base 71.Furthermore, the upward force must be resisted at the cap 21, and inthis instance, the sprocket 51a is relied upon. This hold down functionof the sprocket is accomplished by the side faces of the teeth engagingthe lateral chain links 80. As shown in FIG. 6, the chain 500 may beoptionally mounted adjacent the top of the cap 21.

In view of the foregoing description, it should now be apparent that asimplified and more efficient apparatus and method has been provided forwelding any selected length of flexible pipe than has heretofore beenavailable. The pipe P including intermediate angular section P and thefree end of the pipe P are rotated without hindrance through constantand smooth flexure of said angular section P so that a uniform weldmentis obtained. The cylinder or cap 21 of the welding fixture 10 issecurely mounted by bearings 41, 45 for complete axial and lateralstability that assures accurate rotation and presention of the weld areaA so that the leakproof, uniform weld can be made. When welding largediameter pipes, such as pipe PP (FIG. 6), a pedestal is utilized to thusmake the machine capable of operating on virtually any size flexiblepipe-in diameter, as well as length.

In this disclosure, there is shown and described only the preferredembodiments of the invention, but, as aforementioned, it is to beunderstood that the invention is capable of use in various othercombinations and environments and is capable of changes or modificationswithin the scope of the inventive concept as expressed herein.

We claim:

1. A method of welding a pipe extension to a prefabricated, flexibleelongated pipe comprising the steps of supporting one end of said pipeto be welded upright along a substantially vertical axis, forming anintermediate angular section in said pipe, positioning the extension atsaid one end to define a peripheral weld area, rotating said pipe toturn both ends and the position and in face-to-face contact on said oneend of said pipe, whereby clamping of said extension in position to bewelded is not required.

4. The method of claim 1 whereinthe weld rod performing the weldingoperation is held stationary, whereby the rotating action of said pipesolely applies the uniform bead of weld material.

5. The method of claim 1 wherein is further provided the step of holdingsaid pipe against substantial axial movement.

1. A method of welding a pipe extension to a prefabricated, flexibleelongated pipe comprising the steps of supporting one end of said pipeto be welded upright along a substantially vertical axis, forming anintermediate angular section in said pipe, positioning the extension atsaid one end to define a peripheral weld area, rotating said pipe toturn both ends and the intermediate angular section at substantiallyconstant speed, said angular section being subjected to rotary flexureby said rotating step, and applying a bead of weld material in the weldarea around the periphery of the pipe during rotation whereby a uniformweldment is obtained and extended length of pipe may be welded.
 1. Amethod of welding a pipe extension to a prefabricated, flexibleelongated pipe comprising the steps of supporting one end of said pipeto be welded upright along a substantially vertical axis, forming anintermediate angular section in said pipe, positioning the extension atsaid one end to define a peripheral weld area, rotating said pipe toturn both ends and the intermediate angular section at substantiallyconstant speed, said angular section being subjected to rotary flexureby said rotating step, and applying a bead of weld material in the weldarea around the periphery of the pipe during rotation whereby a uniformweldment is obtained and extended length of pipe may be welded.
 2. Themethod of claim 1 wherein the free end of said pipe is positioned alonga horizontal surface and said angular section extends throughsubstantially 90*.
 3. The method of claim 1 wherein is further providedthe step of freely standing said pipe extension in upright position andin face-to-face contact on said one end of said pipe, whereby clampingof said extension in position to be welded is not required.
 4. Themethod of claim 1 wherein the weld rod performing the welding operationis held stationary, whereby the rotating action of said pipe solelyapplies the uniform bead of weld material.